An MEMS component formed as a microphone is known for example from U.S. Pat. No. 5,490,220 A. In order to produce such a microphone, a thin-film construction comprising at least one membrane embedded into the thin-film construction is produced on a substrate. Said membrane is freed from its embedding in a later method step by virtue of the sacrificial layers that envelop or enclose it being removed by etching.
The functional principle of many MEMS components is based on a capacitor the capacitance of which varies with a deflecting membrane. Accordingly, alongside the electrically conductive membrane, a further conductive layer is also provided as counterelectrode on the substrate, which can be realized within the same layer construction.
Integrated circuits in the form of semiconductor components are required for the electrical signal processing of such an MEMS component, known MEMS components typically being incorporated into a common package with an IC component and thus constituting hybrid components. A further possibility consists in integrating an MEMS component together with an IC component in a module or producing the MEMS component directly on an IC component or connecting it to such a component.
US 2004/0155306 A1 discloses an MEMS component comprising a freely vibrating metallic membrane that is separated by an air gap from an operating electrode arranged underneath on the substrate. For production purposes, firstly a sacrificial layer is produced above the substrate and patterned in such a way that at least one connection region for the membrane is exposed in the substrate. The membrane is subsequently produced over a large area and patterned. Through a hole pattern present in the membrane, the sacrificial layer is etched away underneath, the air gap arising.
US 2004/0126921 A1 discloses an MEMS switch in which a metallic membrane is tensioned above switching and drive electrodes on a substrate in a manner separated by an air gap. The electrical connection of the membrane to a circuit arrangement arranged in the substrate is effected by means of vias produced in a dielectric layer by etching and filling with metal. The air gap below the membrane is produced by etching a sacrificial layer through the membrane provided with a hole pattern. The air gap and hence the distance between the membrane and the drive and switching electrode is set by varying the thickness of the dielectric layer on which the membrane bears on one or both sides.
In the case of MEMS components, the problem generally occurs that the layer construction comprising different material layers, for the MEMS component, can have stresses which are caused by production or generated thermomechanically and which adversely affect the mechanical behaviour of the membrane. Added to this is the fact that MEMS components are preferably produced by means of standardized thin-film methods. An unfavourably strained membrane can lead to a malfunction and an excessively small air gap can lead to a total failure of the MEMS component.